Seven Segments, But Not As We Know Them

We’ve seen a lot of clever re-imagining of the classic 7-segment display, and proving there is still room for something new is [Jack]’s 7-segment “DigiTag” display.

This 3D printable device has a frame into which is slotted three sliders. These sliders can be adjusted individually, mixing and matching the visibility of colored and uncolored areas, to create digits 0-9. We’ve seen some unusual 7-segment-inspired displays before, using from one motor for the whole digit to ones that need one motor per segment, but nothing quite like this approach.

While this particular design relies on the user to manually “dial in” each digit, the resulting key-like assembly (and unique shape for each digit) seems like it could have some interesting applications — a puzzle box design comes to mind.

If you have any ideas of your own on how this could be used, don’t keep them to yourself! Let us know in the comments, below.

Git Your PCBs Online

Last time, I’ve shown you how to create a local Git repository around your PCB project. That alone provides you with local backups, helping you never lose the changes you make to your files, and always be able to review the history of your project as it developed.

However, an even more significant part of Git’s usefulness is the ability to upload our creations to one of the various online Git repository hosting services, and keep it up to date at all times with a single shell command. I’d like to show you how to upload your project to GitHub and GitLab, in particular!

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Robot Blade Runner Turns In World Record Time

While we wish colleges and universities competed more on academics, we can’t deny that more people are interested in their athletics programs. Oregon State, however, has done a little of both since their bipedal robot, Cassie, became the world’s fastest bipedal robot according to the Guinness Book of World Records. You can see a video of the 100 meter run below, but don’t blink. The robot turned in a time of around 25 seconds.

Impressive, but still not on par with Usan Bolt’s time of under 10 seconds for the same distance. If you want to see what that would be like, try running the long way across a football field and see how far you get in 25 seconds. There isn’t a lot of technical detail about the robot, but you can intuit some things from watching it go. You can also find a little more information on the robot and some of its siblings on the University’s website.

If you think robots won’t ever run as well as humans, we used to think the same thing about playing chess. This doesn’t look like we normally envision a bipedal robot. Then again, there isn’t any reason robots have to look, or move, like we do.

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Immersive Cursive: Growing Up Loopy

Growing up, ours was a family of handwritten notes for every occasion. The majority were left on the kitchen counter next to the sink, or in a particular spot on the all-purpose table in the breakfast nook. Whether one was professing their familial love and devotion on the back of a Valpak coupon, or simply communicating an intent to be home before dinnertime, the words were generally immortalized in BiC on whatever paper was available, and timestamped for the reader’s information. You may have learned cursive in school, but I was born in it — molded by it. The ascenders and descenders betray you because they belong to me.

Both of my parents always seemed to be incapable of printing in anything other than all caps, so I actually preferred to see their cursive most of the time. As a result, I could copy read it quite easily from an early age. Well, I don’t think I ever had any hope of imitating Dad’s signature. But Mom’s on the other hand — like I said in the first installment, it was important for my signature to be distinct from hers, given that we have the same name — first, middle, and last. But I could probably still bust out her signature if it came down to something going on my permanent record.

While my handwriting was sort of naturally headed towards Mom’s, I was more interested in Dad’s style and that of my older brother. He had small caps handwriting down to an art, and my attempts to copy it have always looked angry and stilted by comparison. In addition, my brother’s cursive is lovely and quick, while still being legible.

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close-up image of a philodendron houseplant with electrodes attached, connected to a robot arm holding a machete

(Mostly) Harmless Houseplant Wields Machete

In a straight fight between a houseplant and a human, you might expect the plant to be at a significant disadvantage. So [David Bowen] has decided to even the odds a little by arming this philodendron with a robot arm and a machete.

The build is a little short on details but, from the video, it appears that adhesive electrodes have been attached to the leaves of the recently-empowered plant and connected directly to analog inputs of an Arduino Uno.  From there, the text tells us that the signals are mapped to movements of the industrial robot arm that holds the blade.

It’s not clear if the choice of plant is significant, but an unarmed philodendron appears to be otherwise largely innocuous, unless you happen to be a hungry rodent. We hope that there is also a means of disconnecting the power remotely, else this art installation could defend itself indefinitely! (or until it gets thirsty, at least.) We at Hackaday welcome our new leafy overlords.

We have covered the capabilities of plants before, and they can represent a rich seam of research for the home hacker.  They can tell you when they’re thirsty, but can they bend light to their will?  We even held a Plant Communication Hack Chat in 2021.

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Electric Guitar Shocks You For Missing A Note

Rocksmith is a popular video game that works like Guitar Hero, but with a real guitar. You have to play well and hit the right notes, or the game penalizes your score. [Lightwing] took the stakes up a notch, though, adding a system that shocks the player every time they fail.

To achieve this, it was necessary to detect when the player missed a note. Initial attempts involved using Tensor Flow AI to detect the game state from the screen, but it was unreliable. Instead, the game’s memory was read to achieve detection. When the player misses a note, a certain section of memory changes, and a script reads the change in game state. It then sends a signal to an Arduino which triggers the stun gun’s fire button, which shocks the player holding the guitar.

As you might expect, the documentation for this project includes a video which involves plenty of gratuitous electric shocks when [Lightwing] makes mistakes. Fair warning — there’s plenty of colorful language when the stun gun fires. Generally, a powerful shock ends with screams a dropped guitar, and too much fear to continue.

It’s painful enough that it’s probably not a useful teaching tool for learning the guitar. We’ve seen similar shocking builds before, too, like this simple wire game.

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Fixing A 30-year Old Roland Bug

The Roland CM-500 is a digital synthesizer sound module released in 1991 that combines two incredibly powerful engines into one unit. However, in 2005 enthusiasts of the Roland MT-25 (one of the engines that went into the CM-500) noticed a difference between the vibrato rate on the MT-25 and the CM-500, rendering it less useful as now midi files would need to be adjusted before they sounded correct. Now thirty-something years later, there is a fix through the efforts of [Sergey Mikayev] and a fantastic writeup by [Cloudschatze].

They reached out to Roland Japan, who decided that since the device’s lifecycle had ended, no investigation was warranted. That led the community to start comparing the differences between the two systems. One noticeable difference was the change from an Intel 8098 to an 80C198. In theory, the latter is a superset of the former, but there are a few differences. First, the crystal frequency is divided by three rather than two, which means the period of the LFO would change even if the crystal stayed the same. Changing the 12 MHz crystal out for 8 MHz gave the LFO the correct period, but it broke the timings on the MIDI connection. However, this is just setting the serial baud rate divisor, which requires changing a few bytes.

Replace the ROM chip with a socket so you can slot your newly flashed PDIP-28 64kx8 ROM into a quick desoldering. Then swap the crystal, and you’ll have a machine that matches the MT-25 perfectly. The forum post has comparison audio files for your enjoyment. Finally, if you’re curious about other fixes requiring an inspiring amount of effort and dedication, here’s a game installer that was brought back from the dead by a determined hacker.